Readily renewable sectionalized trommel



Feb. 21, 1967 F. P. MORAWSKI ET AL 3,305,090

READILY RENEWABLE SECTIONALIZED TROMMEL 5 Sheets-Sheet 1 Filed April 14,1964 Feb. 21, 1967 F, P. MORAWSKI ET AL READILY RENEWABLE SECTIONALIZEDTROMMEL 3 Sheets-Sheet 2 Filed April 14, 1964 j j w I l m O L I a I h CL wum Tu Wm 1 I 1 1 h .LL

Feb. 21, 1967 p W K ET AL 3,305,090

READILY RENEWABLE SECTIONALIZED TROMMEL Filed April 14, 1964 5Sheets-Sheet 5 United States Patent 3,305,090 READILY RENEWABLESECTIGNALIZED TROMMEL Frederick Peter Morawski and Paul L. Fontecchio,both of Aurora, Minn., assignors to Erie Development Company, Cleveland,Ohio, a corporation of Delaware Filed Apr. 14, 1964, Ser. No. 359,741 3Claims. (Cl. 209-488) This invention relates to screens, and morespecifically to improvements in rotatable circular screens or trommels.The invention, which includes both process and apparatus aspects, findsparticular application in connection with a cylindrical or frustoconicaltrommel of a balling drum of the general type disclosed in US. PatentNo. 2,831,210, De Vaney.

The apparatus disclosed in said patent functions to form loose, moist,very finely divided solids into small balls or pellets by prolongedlyrolling the fine material, together with nuclei or seed balls, in aninclined, generally horizontal rotatable balling drum and screeningundersized balls and loose material from the stream of materialconstantly discharging at the low end of the drum.

The aforesaid trommel consists essentially of a cylindricalor,frustoconicalskeletal framework made up from an array of lengths ofangle stock or girders or the like supporting members which are held indesired spaced relation by one or more transverse bands disposed at a 90angle to said supporting members. The screening surface of the trommelis formed from an array of generally parallel, spaced wires or rods orequivalent screening members secured in any suitable manner to saidsupporting members, the width of the interstices between each twoadjacent screening members determining the split as between (a) thespherical or spheroidal bodies which are retained on the trommel and aredischarged at the low edge of the latter and (b) the nuclei and loosematerial which drop through said interstices (i.e., are screened out)and then returned to the feed end of the balling drum for a furtherpassage through the latter. The trommel may be constructed as anintegral part of the balling drum; or, it may be physically andfunctionally distinct from the balling drum, being independentlymountedat the discharge end of the drumfor rotation and disposed toreceive any and all material discharged from the drum.

Where-as is the case in the balling of finely divided mineral solids ofthe type of iron ore concentratesthe material being balled is abrasivewith respect to the metal from which the spaced wires or rods of thetrommel are formed, there exists a wear problem necessitatingre-building, renewing or repairing the trommel as individual wires orrods become worn through or so badly worn as to cease to screen atdesired tolerances. conventionally, such renewal of a trommel has meantwithdrawing the involved balling drum from service, removing the entiretrommel from the balling drum, rebuilding the removed trommel in itsentirety and finally mounting the rebuilt trommel on the balling drum.

It has now been found that the trommel may be so formed that its renewalmay be effected much more quickly than heretofore and with verysubstantial savings in cost of renewal (including both as to down timeand as to labor cost and as to materials cost) and hence in the overallcost of the screening operation.

While the trommel of the present invention superficially appears to beidentical with the conventional trommel it differs from the latter inbeing formed from a skeletal supporting structure to which there arereadily detachably secured an array of individual panels each of whichis independently detachable from and re-attachable to said supportingstructure. Preferably, the panels are interchangeable. Each panel iscomposed of .a sub-frame structure to which there are secured aplurality of spaced, parallely disposed, arcuate rods having a modifiedT shape (with head and web portions) in cross-section. Preferably, thesub-frame structure comprises a plurality of inverted U-holders-eachhaving a length equal to the width of the individual screeningpanelprovided with suitable slots or recesses in which slots there arefitted the web portions of the arcuate rods, these rods being tightlyfitted into said slots and secured in place therein by means ofelongated pinning members each of which latter extends through one Uholder and through apertures provided in the webs of the rods.

The assembled trommel screen consists (over and above the aforesaidpermanent skeletal supporting structure which is bolted in place at thedischarge end of the balling drum proper) of .at least one ringandadvantageously a plurality, e.g., three or more, of ringsof the abovescreen panels disposed with their rods running peripherally of thetrommel, each such ring being composed of a plurality of panels, e.g.,six more or less panels, the arcs of curvature of which add to acomplete circle. The individual panels are disposed in the trommel perse by seating its U-holders on the inner edge portions of supportingframework members of the trommels permanent structure, and the panelsare detachably secured to supporting framework members by means of aplurality of spring clips each of which embraces a U holder and aframing member of the supporting structure.

For assembling a panel there is used an assembly jig or positioningfixture comprising two end boards with a plurality of spaced supportingarms fixed between them, with their upper edges at a slightly lowerlevel than that of the upper edges of the end pieces. The end pieces arearcuate, with the same radius of curvature as that of the rods.Preferably, there are the same number of supporting arms as there areU-holders per screen panel. Preferably, also, the cross-sectionalcharacteristics of the supporting arms are made similar to those of theparts of the permanent skeletal framework of the trommel, so that whenthe completed panel is installed in the trommel, it will be located inthe latter by seating its U- holders on the inner edge portions of saidframework parts. Accordingly, the spacing of said arms is to be the sameas is the spacing of said framework parts.

In assembling a screen panel U-holders are placed over the supportingarms, and the trommel rods are fitted into the slots of the U-holderswith their pre-formed pin apertures positioned within the U-holders.Then, the pinning members are inserted above the upper edges of thesupporting arms and beneath the U-holders, passing through the pinningapertures in the web portions of the rods, the diameter of theseapertures being so selected that the pinning members have a snug fit inthe pinning apertures of the rods.

As will, of course, be understood, a used panel may be renewed byreplacing only the badly worn rods with new rods.

In replacing a screen panel which shows undesirably severe wear as tosome one or more of its rods, the spring clips tying that panel to theskeletal supporting structure of the trommel are disengaged, the oldpanel is lifted out, a new panel is substituted in the place of the oldone, and the newly placed panel is tied in place by means of a pluralityof spring clips.

The invention will now be described in greater particularity withreference to the accompanying drawing, in which- FIG. 1 is a top planview of a completed screen panel, according to the present invention,supported on an assembly jig;

FIG. 2 is a side elevational view of the panel and jig shown in FIG. 1;

FIG. 3 is a detailed showing of a fragmentary portion of the view inFIG. 2 illustrating the mode of securing the screen panel either-asillustrated-to a supporting arm of the assembly jig or to skeletalframework of the tromrnel;

FIG. 4 is a top plan view of the showing in FIG. 3;

FIG. 5 is a vertical sectional view of a portion of a screen panel andof the appertaining part of an assemy i F165. 6 and 7 are perspectiveviews, as assembled and exploded, respectively, of a portion of anassembly jig and partially assembled screen panel; and

FIG. 8 is a fragmentary end view of a portion, only, of an assembledsectionalized trornmel according to the present invention, showing oneend of one panel and adjacent portions of two laterally adjacent panelsin place on the skeletal supporting structure of the trommel.

In FIGS. 1 and 2 an assembly jig for assembling an individual panel iscomposed of a stand, consisting of vertical members 1 and horizontalmembers 2, for arcuate end boards 3, 3 with their transverse supportarms 4, 4 (here shown as being six in number). Inverted U-hoiders 6, 6are disposed on the arms 4, 4, in the slots 8, 8 of which U-holdersthere are fitted the web portions 10, 10 of arcuate trommel rods R, thehead portions 11, 11 of which rods extend above the U-holders. Apertures14 are provided in the web portions 10, 10 of rods R in line withsupport arms 4, 4, and elongated pinning members 15, 15 are inserted inthese apertures to tie the several parts of the screen panel together.These parts can be, and usually are, secured in place, on the assemblyjig, by means of spring clips 18, 18. These spring clips moreparticularly function-in the use of the screen panel in the trommel-tosecure the panel to the supporting framework members 20, (see FIG. 8) ofthe trommel.

A panel is installed in the trommel by locating the panel with itsU-holders over the supporting framework members 20, 20, seating theU-holders on the latter members, and securing the panel to members 20,20 by applying the spring clips 18, 18. In case the location of theU-holders, in the panel, is out of phase with the spacing of supportingframework members 20, 20, the U-holders may be moved-to right or toleft-to bring them into co-operating relationship with parts 20, 20. Aswill be apparentto any reader, demounting a worn panel is eifected byremoving the spring clips and lifting out the panel.

We claim:

1, A readily renewable sectionalized cylindrical screen structure forsizing particulate material being discharged from a rotatable cylinder,which comprises a cylindrical skeletal supporting framework comprising aplurality of elongated generally parallel spaced ribs, said frameworkbeing adapted to be fixed endwise to an end of such rotatable cylinder;

a plurality of arcuately concave screening panels adapted to bedetachably secured transverse to the ribs of said framework toconstitute in toto a cylindrical screen coaxial with such cylinder,

each said panel being constituted by a sub-frame structure and aplurality of parallel spaced arcuate rods detachabiy secured thereon;

said sub-frame structure including a plurality of spaced generallyparallel inverted U-holders having a length substantially equal to thewidth of the panel and having in the base of the U a plurality of spacedslots accommodating portions of said rods;

and means detachably securing said panels to the ribs of said skeletalsupporting framework with the arcuate rods oriented in a directiongenerally normal to the longitudinal axis of said cylindrical frame workand with the confronting ends of the rods of said panels in substantialalignment with each other.

2. The sectionalized cylindrical screen defined in claim 1, in whichsaid rods have a cross-sectional contour in the form of a modified Twith head and web portions integral with each other, the web portionsfitting into the slots in said U-holders, in that the web portions ofthe rods are provided with apertures at loci corresponding to thespacing of said U-holders, and in that elongated pinning members aredisposed within said Uholders, said pinning members extending throughthe apertures in the web portions of said rods.

3. The sectionalized cylindrical screen defined in claim 1, in whicheach individual panel spans a plurality of ribs and is secured to saidribs with its U-holders seated on said ribs, and in which the detachablesecuring means are spring clips each of which embraces a U-holder and arib.

References Cited by the Examiner UNITED STATES PATENTS 380,348 4/1888Prinz 209-407 X 1,769,128 7/1930 Fisher 209-395 X 1,812,121 6/ 1931Sklovsky. 2,633,852 4/1953 Lupton 209-407 X 2,711,557 6/1955 Russell18-1 2,831,210 4/1958 De Vaney 18-1 2,834,043 5/1958 Haley et a1. 18-13,042,206 7/1962 Olender 209-405 X 3,073,449 1/1963 Iohanningmeier209-11 X 3,081,874 3/1963 Corbin 209-403 X FOREIGN PATENTS 14,973 7/1901 Great Britain, 243,214 11/1925 Great Britain.

FRANK W. LUTTER, Primary Examiner.

WILLIAM J. STEPHENSON, HARRY B. TI-IORNTQN,

R. HALPER, Assistant Examiners, i

1. A READILY RENEWABLE SECTIONALIZED CYLINDRICAL SCREEN STRUCTURE FORSIZING PARTICULATE MATERIAL BEING DISCHARGED FROM A ROTATABLE CYLINDER,WHICH COMPRISES A CYLINDRICAL SKELETAL SUPPORTING FRAMEWORK COMPRISING APLURALITY OF ELONGATED GENERALLY PARALLEL SPACED RIBS, SAID FRAMEWORKBEING ADAPTED TO BE FIXED ENDWISE TO AN END OF SUCH ROTATABLE CYLINDER;A PLURALITY OF ARCUATELY CONCAVE SCREENING PANELS ADAPTED TO BEDETACHABLY SECURED TRANSVERSE TO THE RIBS OF SAID FRAMEWORK TOCONSTITUTE IN TOTO A CYLINDRICAL SCREEN COAXIAL WITH SUCH CYLINDER, EACHSAID PANEL BEING CONSTITUTED BY A SUB-FRAME STRUCTURE AND A PLURALITY OFPARALLEL SPACED ARCUATE RODS DETACHABLY SECURED THEREON; SAID SUB-FRAMESTRUCTURE INCLUDING A PLURALITY OF SPACED GENERALLY PARALLEL INVERTEDU-HOLDERS HAVING A LENGTH SUBSTANTIALLY EQUAL TO THE WIDTH OF THE PANELAND HAVING IN THE BASE OF THE U A PLURALITY OF SPACED SLOTSACCOMMODATING PORTIONS OF SAID RODS; AND MEANS DETACHABLY SECURING SAIDPANELS TO THE RIBS OF SAID SKELETAL SUPPORTING FRAMEWORK WITH THEARCUATE RODS ORIENTED IN A DIRECTION GENERALLY NORMAL TO THELONGITUDINAL AXIS OF SAID CYLINDRICAL FRAMEWORK AND WITH THE CONFRONTINGENDS OF THE RODS OF SAID PANELS IN A SUBSTANTIAL ALIGNMENT WITH EACHOTHER.